package com.algorithm.other;

/**
 * @author: tzj
 * @create: 2022-10-09
 **/
public class Fib_509 {

    public static void main(String[] args) {
        System.out.println(fib_2(4));
    }

    public static int fib(int n) {
        if (n < 2) {
            return n;
        }
        return fib(n - 1) + fib(n - 2);
    }

    public static int fib_2(int n) {
        if (n < 2) {
            return n;
        }
        int[] dp = new int[n + 1];
        dp[0] = 0;
        dp[1] = 1;
        for (int i = 2; i <= n; i++) {
            dp[i] = dp[i - 1] + dp[i - 2];
        }
        return dp[n];
    }
}
